Global climate change influences ecosystems across the world. Alpine plant communities have already experienced serious impacts, and will continue to do so as climate change continues. The aim of our study was to determine the sensitivity of woody and herbaceous species to shifts in temperature along an altitudinal gradient. Since 1994, park rangers have been making phenological observations at 24 sites from 680 to 1425 m a.s.l. Each year 21 plant species were observed once or twice weekly from March to July; with a main focus on flowering and leaf unfolding. Our study showed a very high degree of dependence of phenophases and species on inter-annual temperature variation and altitude. Averaged over all species and phenophases, there was a delay of 3.8 days with every 100 m increase in altitude and, across all elevations, an advance of phenophases of 6 days per 1 °C increase in temperature. Temperature lapse rates assessed indirectly by phenology, as the quotient of altitudinal to temperature response coefficients, were higher than directly calculated from March to July mean temperatures, most likely due to snow effects. Furthermore, a significant difference in sensitivity to temperature change was found between growth forms (herbs versus trees). Sensitivity was less pronounced in events occurring later in the season. Our results show that species reactions will differ in magnitude during global warming. Consequently, impacts of shifts in the timing of phenological events on plant migration and plant-pollinator interactions due to rising temperatures should be considered at the species level.

Plant communities in the European Alps are assumed to be highly affected by climate change, as the temperature rise in this region is above the global average. It is predicted that higher temperatures will lead to advanced snowmelt dates and that the number of extreme weather events will increase. The aims of this study were to determine the impacts of extreme climatic events on flower phenology and to assess whether those impacts differed between lower and higher altitudes. In 2010, an experiment simulating advanced and delayed snowmelt as well as a drought event was conducted along an altitudinal transect approximately every 250 m (600–2000 m above sea level) in the Berchtesgaden National Park, Germany. The study showed that flower phenology was strongly affected by altitude; however, there were few effects of the manipulative treatments on flowering. The effects of advanced snowmelt were significantly greater at higher than at lower sites, but no significant difference was found between both altitudinal bands for the other treatments. The response of flower phenology to temperature declined through the season and the length of flowering duration was not significantly influenced by treatments. The stronger effect of advanced snowmelt at higher altitudes may be a response to differences in treatment intensity across the gradient. Consequently, shifts in the date of snowmelt due to global warming may affect species more at higher than at lower altitudes, as changes may be more pronounced at higher altitudes. These data indicate a rather low risk of drought events on flowering phenology in the Bavarian Alps.

The BBCH scale is a two-digit key of growth stages in plants that is based on standardised definitions of plant development stages. The extended BBCH scale, used in this paper, enables the coding of the entire development cycle of all mono- and dicotyledonous plants. Using this key, the frequency distribution of phenological stages was recorded which required a less intense sampling frequency. The onset dates of single events were later estimated from the frequency distribution of BBCH codes. The purpose of this study was to present four different methods from which those onset dates can be estimated. Furthermore, the effects of (1) a less detailed observation key and (2) changes in the sampling frequency on estimates of onset dates were assessed. For all analyses, phenological data from the entire development cycle of four grass species were used. Estimates of onset dates determined by Weighted Plant Development (WPD), Pooled pre-/post-Stage Development (PSD), Cumulative Stage Development (CSD) and Ordinal Logistic Regression (OLR) methods can all be used to determine the phenological progression of plants. Moreover, results show that a less detailed observation key still resulted in similar onset dates, unless more than two consecutive stages were omitted. Further results reveal that the simulation of a less intense sampling frequency had only small impacts on estimates of onset dates. Thus, especially in remote areas where an observation interval of a week is not feasible, estimates derived from the frequency distribution of BBCH codes appear to be appropriate.

Question: Re-wetting drained peatlands is a common restoration method to reduce carbon loss, but little is known on its likely consequences on reproductive plant development, especially in a warming world. Thus, the aim of this study was to test whether the phenological development of plant species in a peatland ecosystem changed with higher temperatures, increased water table level or a combination of the two.Location: Fen peatland site in Bavaria, Germany.Methods: In 2010, manipulative experiments with two different treatments (control and warming) and in 2011 with four different treatments (control, warming, increased water table level, warming + increased water table level) were conducted. Temperature was raised 0.4-1.5°C with open-top chambers (OTCs) from August 2009 onwards, and water table level was elevated 12 cm using a pumping system, however the latter was not continuous for the whole growing season of 2011 due to technical difficulties. Phenological development of different grassland species was observed weekly using the BBCH code. Attention focused on reproductive phenology (from flower development to fruit senescence) and on key single phenological phases, such as flower development, flowering, ripening and fruit senescence, as well as the duration of key phases. Additionally, vegetation height was measured.Results: Our study showed that higher temperatures advanced reproductive phenology and most key phases, except fruit senescence. Water table manipulations had no significant influence on phenology. The duration of key phases was generally not significantly influenced by treatments, whereas vegetation height differed between control and higher temperature plots. Conclusion:In general, raising the water table to reduce carbon release from drained peatland sites will not dramatically affect phenological development of grassland species, whereas increased temperatures will affect reproductive phenology.

The purpose of the paper was to present and compare four different methods to analyze phenological data of populations recorded on a refined BBCH scale in order to estimate onset dates for each phenological stage. The OLR method described is one way to determine those onset dates. Compared to the other methods investigated, the OLR method is based on the frequency distribution over time which includes the entire progression of plants in the model and not only the progression of a single stage. However, the equation that describes the OLR model (Eq. 4) was wrong in the original version of the manuscript:is the probability and Y is the ordinal response variable, α is the intercept parameter, β i the slope parameters and x i the explanatory variable (here time). Thus, please consider the corrected equation, which reads as follows:where p=P(Y≥i|t) is the cumulative probability that the observed phenological phase Y (coded as ordinal integer) is above a certain phase i given the time t, α i are the intercept parameters for each phase i, β the slope parameter for time t (here: day of year).The online version of the original article can be found at http://dx